Apparatus for cutting and polishing precious stones



(No Model.)

11. PASSMORE. APPARATUS FOR CUTTING AND POLISHING PRECIOUS STONES.

No. 510,817. Patented Dec. 12, 189s.

IIIII IIIIIIIII ll/ibvesaef. 7 lcvenkm mub'w/Pa5swwre.

UNITED STATES PATENT OFFICE.

EDIVIN PASSMORE, OF SOMERVILLE,

ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, OF FIVE -EIGHTHS TO ARTHUR H. PRAY AND EDWIN B. COX, OF BROOKLINE, MASSACHUSETTS.

- APPARATUS FOR CUTTING AND POLISHING PRECIOUS STONES.

SPECIFICATION forming part of Letters Patent No. 510,817, dated December 12, 1893.

Application filed March 1 3, 1 8 9 3 is a specification, like letters and figures on the drawings representing like parts.

In the art of cutting stones for jewels notwithstanding the fact that mechanical means have been devised the lapidary has commonly affixed the stone to the end of a stick and has then held the stone on the lapidarys wheel,

making one facet after another, the pointed upper end of the stick being rested against a notch in an inverted cone'. This plan requires for the production of reasonably accurate Work a high order of skill gained only by long practice. Attempts have been made, as in United States Patent N 0. 479,452, granted to me July 26, 1892, to hold and control the stick automatically, but such plan is not as satisfactory as I could desire because the lapidary should at all times be able to see, instantly and frequently the progress of the facets, and especially of the first facet, as on it all the facets of that row depend, and in practice all the facets of a row should be at just the same angle.

The lapidary who holds the stick in his hand may quickly and easily inspect the stone, but he finds with ordinary appliances great diffi culty in controlling the angle of presentation of the stick and stone to the wheel, and hence only skilled workmen can be employed.

I have aimed to, and have produced a machine wherein all the advantages to be derived from holding the stick by hand are retained, and in addition thereto, the lapidary,- one facet having been made,-is thereafter enabled to make every other facet at exactly the same angle, and the parts are also so constructed as to insure the step by step rotation of the stick in such manner as to accurately space the facets, v

In my invention I have devised a stickholder, and with it I have combined a foot of such shape that it may be readily applied to or removed from an adjustable fulcrum block Serial No. 465,760. (No model.)

at the will of the lapidary who holds the stickholder in his hand, the shape of the said foot being such as to enable the lapidary to balmice the same accurately and move the stone toward or from the wheel to get the proper first facet, the shape of the foot shown by me also being such as to insure exactly the same position for the stick-holder in the fulcrum block when reapplied. One facet of a row having been determined, the lapidary moves into working position a gage which acts as a stop to limit the extent of movement of the stick-holder toward the wheel during the cutting of every succeeding facet in said row on that stone. Between the foot and stick-holder I have applied a step by step ratchet device by which to effect the step by step rotation of the stick-holder preparatory to grinding each facet. The fulcrum block is made adjustable vertically with relation to the lapidarys Wheel, and so also preferably the head which is directly supported by the post is made adj ustable about said post.

Figure 1,in elevation, partially broken out, however, shows my improved apparatus, together with part of a lapidarys wheel. Fig. 2, is an enlarged view of the stick-holder and stick, the latter being in section, with its attached foot, the latter being mostly in elevation; Fig. 3, a top or plan view of the apparatus shown in Fig. 1, the stick-holder and the lapidarys wheel being, however, omitted. Fig. 4 is a section in the line m Fig. 2. Fig. 5 is a section in the line at, Fig. 2. Fig. 6 is a detail to the left of the line :2 Fig. 1; Fig. 7, an enlarged detail of the fulcrum block. Fig. 8 shows the sleeve h detached.

Referring to the drawings, let A represent part of a bench or table havingasocketpiece A attached thereto, in which is adjustably held the rod A by a set screw a,'said rod having attached to it an arm A, upon which is erected a post B.

The lapidarys wheel P is carried by a suitable rotating shaft P'.

The parts so far referred to are commonly in use by lapidaries q The post B receives upon it the hub C of a head, the other part of the head being a bracket 0'. The hub is shown as provided [00 with a set screw 0, by which to fasten it in position upon the post, the loosening of the screw, however, permitting the hub to be adjusted about the post, the said hub having also preferably at its upper end a plate C provided with a threaded orifice, in which is inserted an adjusting device 0 made as a screw, the end of which abuts against the post, the rotation of the adjusting device when the set screw 0 is loosened, enabling the head to be adjusted vertically on the post with relation to the said wheel P. The bracket portion of the head has, as herein shown, suitable pivot screws a, which serve to pivotally mount in the head a scale bar I) having upon one edge a suitable index so as to gage to a nicety the position of the fulcrum block D, the said scale bar being slotted, as best shown in Fig. 6, to receive a screw-threaded stem 1) extended back wardly from the fulcrum block, said screw having applied to it a suitable nut, as W, preferably provided with a handle, by which to turn the same easily,awasher b being in practice interposed between the said nut and scale bar.

The fulcrum block, shown best in Figs. 1 and 7, has a foot-receiving surface d, shown as a V-shaped notch adapted to receive the tapered or V-shaped edge e of the foot E, to be described, the foot being free to rock on said foot-receiving surface, the longitudinal movement of the foot over the surface being, however, restrained by a pin on one entering a projection from the other, as for instance, a pin cl on the fulcrum block to receive the notch c of the foot. The fulcrum block has pivoted upon it atf a stop f, shown as an arm slotted at 2, said slot receiving through it the shank of a stud screw f by which to clamp the stop in the position required for the second and other facets to be cut on the stone in any one row. The stop has co-operating with it a spring 3, one end of which is fixed to the pivot f, while the other end is connected to the stop, the spring acting normally to move the stop in the direction of the arrow upon it in Fig. 1, the spring moviug the stop in that direction whenever the stud screw, which constitutes a locking device for the stop, is turned in a direction to relax its hold upon the stop.

The foot E referred to consists essentially of the V-shaped portion having a shank e provided with an enlargement e and a stem c, best shown in Fig. 2, said stem entering the hollow upper end of the stick-holder g, said stick'holder being interposed between a flanged portion a of the enlargement e and a sleeve it, said sleeve, shown best in Fig. 8, and in section in Fig. 4, havinga series of pockets h adapted to receive a locking device 72 shown as a pin connected with an ear lb of a slidebar 71.4 having, as shown, pinned to it a fingerpiece h, said slide-bar being surrounded by a spiral or other suitable spring h, which normally acts to keep the locking device 7L2 in one of the pockets h of the sleeve.

In practice, the small or lower end of the sleeve h is provided with two notches 4:, 5, as shown best in Fig. 8, one or the other of which will be engaged by the pin or projection m carried by the stick-holder g. The stickholder, chambered at its lower end and suit ably split to constitute a chuck, receives within it the stick m, the lower end of which is suitably cupped to receive and center the stone to be cut orpolished, the chuck portion of the stick-holder having a suitable movable ring or collar m by which to close the chuck portion of the holder firmly upon the stick.

In operation, the lapidary will fix the stone to the stick, and will then adjust the fulcrum block into approximately its proper position for the work to be done, and he will fasten the stop f back, so as not to be in the way of the movement of the stick-holder. The stick having been provided with a stone, the lapidary will grasp in one hand the stick-holder, and will place the foot in the foot'receiving surface of the fulcrum block, and will hold the stone upon the rotating wheel P, and from time to time, as judgment indicates, he will remove the foot from the fulcrum block, which can be readily done as he is grasping the stick-holder in his hand, and will critically examine the facet being cut, and he will again apply the foot to the fulcrum block and again remove it until the first facet being made has been brought to the desired angle or size suitable for the particular stone which is to be cut or polished, and, the one facet having been made, the lapidary will release the looking device f let the spring 3 throw the stop forward against the stick-holder, while the foot is in the block and the stone rests upon the wheel, and the stop will then be again locked in position. The proper position hav, ing been gained for the stop the lapidary is certain that every subsequent facet in that row will be just like the first as soon as the stick-holder meets the stop, and the stop positively prevents any further movement of the stick-holder with its stone toward the wheel after the facet has been brought to the established bevel.

It will be remembered that many precious stones contain a great number of facets, and if a stone is to have, say, thirty-two facets, it is preferable to make sixteen of them at uniform distances apart, and then make the other sixteen between the sixteen facets first out, two rounds of the sleeve insuring thirty-two facets.

I have shown the upper end of the sleeve h as provided with sixteen pockets, and the lower end of the sleeve with two notches. Now, when the pin or projection m enters, say, the notch 5, as is supposed to be the case in Figs. 2 and 5, the tubular part g of the stick-holder is fixed to the sleeve. It will be remembered that the sleeve has a series of pockets, and the sleeve is adapted to be rotated about the stem e of the foot whenever the slide-bar 77.4 is pushed in far enough to IIO withdraw the pin 71.2 from one of the pockets, the lapidary effecting the rotation of the sleeve one step by hand. The lapidary does rotate the sleeve and stick-holder uniformly by hand one step after each facet is made, for the first round of thestone. After this, how- I ever, the lapidary may pull, the stick-holder out from the sleeve far enough to turn the stick-holder in the sleeve and put the pin or projection on into the notch 4, and during the next complete rotation of the stick-holder and sleeve, portionsof the stone between portions already faceted will be put in position to be acted upon by the wheel P. The stop f will preferably be concaved, as best shown in Fig. 3, to prevent any possibility of lateral motion or shake of the stick-holder during the grinding operation upon the stone. For the best results, I prefer that the end of the foot and the foot-receiving surface shall be shaped to resemble the bearings of a scale beam and its supports as the finer the points of contact between the foot and fulcrum block, the less the friction. The end of the foot fits readily into the recess in the fulcrum block, as a chisel enters a hole.

With my improved apparatus, a person having but limited experience can accomplish work which heretofore has required a most skilled operator, and a skilled operator with an apparatus such as described may accomplish a very much greater amount of work than with any other apparatus known to me.

Inasmuch as the stick holderis grasped and retained in the hand of the operator during the entire grinding or polishing operation, it follows that the operator adjusts the pressure on the stone to the particular requirements of the stone, the grinding of one or another facet requiring more or less time, but never going beyond the point determined by the position of the stop.

Where the stick-holder is controlled mechanically it is impossible to get and maintain such delicate presentation of the stone to the wheel, as is required in many instances.

It is important in lapidary work to control the presentation of the stone to the wheel in the most delicate manner, to thus avoid breaking stones which are oftentimes very valuable.

The slot e co-operating with the pin d forms a device to prevent lateral slipping of the foot of the stick-holder on the fulcrum block, but this invention is not limited to the exact devices shown for the purpose, as many equivalent devices might be employed.

Having described my invention, What I claim as new, and desire to secure by Letters Patent, is

1. The combination in an apparatus for grinding and polishing precious stones, of a fulcrum block having a foot-receiving recess, with a stick-holder having a foot to enter said recess, and with devices to prevent the lateral slipping of the said foot in said recess, substantially as described.

2. The combinationin an apparatus for grinding and polishing precious stones, of a pivoted gage-bar, as b, a suitable support for the same, and a fulcrum block adjustably mounted on-said gage-bar, and provided with a foot-receiving recess, of a stick-holder having a foot shaped to enter and tip in said recess, as and for the purposes set forth.

3. In an apparatus for grinding and polishing precious stones, a stick-holder provided with afoot having an extended bearing surface, combined with a fulcrum block having a foot-receivingsurface, to operate, substantially as described.

4.. A stick-holder having an elongated V- shaped foot, provided with a notch, combined with a fulcrum block having a foot-receiving recess provided with a projection to cooperate with said notch, substantially as described. v

5. A stick-holder provided with a foot and a fulcrum block to,receive said foot, combined with a stop to limit the extent of the rocking movement of said foot in or with relation to said fulcrum block and to and from the wheel, substantially as described.

6. A stick-holder provided with a foot, and a fulcrum block to receive said foot, combined with a stop to limit the extent of rocking movement of said foot in or with relation to said fulcrum block, and with a gage-bar, and means to adjust the block on said gage-bar, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

EDWIN PASSMORE.

Witnesses:

GEO. W. GREGORY, ARTHUR H. PRAY. 

